alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET HUNTING Possible RTF File With Obfuscated Version Header"; flow:established,to_client; file_data; content:"{|5C|rt"; within:4; content:!"f"; within:1; classtype:bad-unknown; sid:2026863; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_01_30, deployment Perimeter, former_category INFO, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_11_29, mitre_tactic_id TA0005, mitre_tactic_name Defense_Evasion, mitre_technique_id T1027, mitre_technique_name Obfuscated_Files_or_Information;)